This is the renewal application for Years 16-20 of a training program designed to produce investigators at the cutting edge of research in the area of pediatric gastroenterology. Trainees will be at the postdoctoral level and will be a mixture of M.D.'s supported for 3 years and Ph.D.s supported for 2 years. To allow recruitment of two new M.D.s and one new Ph.D. trainee each year, a total of 7 stipends are required. For all trainees, the program has traditionally placed strong emphasis on molecular biology, the rationale being that molecular approaches are of central importance in both study and treatment of diseases associated with pediatric gastroenterology. In the current proposal there is also emphasis on bringing the results of molecular research to the bedside. The mentors (5 M.D.'s, two M.D./Ph.D. and 9 Ph.D.'s) represent a multidisciplinary group of experienced investigators from various departments at Baylor College of Medicine (BCM) and University of Texas Health Science Center (UTHSC). Their research covers four broad areas that are important to pediatric gastroenterology, namely: mucosal biology;molecular hepatology;immunology and inflammation;and translational biology. All mentor laboratories are well equipped and well funded. All 16 faculty members are already associated with the program and have excellent track records of interaction and participation in program activities. The Program Director, Dr. Susan J. Henning, Ph.D., maintains ultimate authority for the overall program and manages day-to-day operations. Beginning in Year 16 she will be assisted by two Associate Program Directors (Robert J. Shulman, M.D. for clinical research and Douglas G. Burrin, Ph.D. for basic science research). Major administrative decisions (e.g., selection of trainees) are handled by an Executive Committee, which includes the Program Director and Associate Directors, three other program faculty and a senior faculty member not associated with this grant. The training program for M.D. fellows includes research rotations to facilitate selection of a mentor, individual research committees, a written research proposal which has to be defended to the research committee, and periodic reviews of progress. Both M.D. and Ph.D. fellows are required to attend a biweekly research seminar series and a monthly journal club. All fellows must present at both of these fora on an annual basis. Trainees are selected from a highly competitive applicant pool that already exists at BCM. Past trainees have performed well with 75% of M.D.'s and 78% of Ph.D.'s remaining in academia. The majority of these have been successful in securing either internal or external funding for their research including NIH F32s, K08s and K22, as well as other competitive sources. The current proposal includes several new features designed to enrich and enhance the existing program.